pH of pool water

Maintaining the pH of pool water at the correct level is the best thing you can do for your pool. This is because it will help maintain the pool surface and the safety of the water for swimmers. Remember, it is generally suggested that you check the pH of your pool every two weeks in summer and every month in winter.

“Did you know that most surface issues occur because the pH of the water has been too high or low for a long period of time.”

What is the right pH of pool water?

For most pools around the world, it is recommended that you maintain the pH of pool water at 7.4. This is because the pH of our eyes (tears) is also 7.4. This means that if the pH of the water is kept at 7.4 then your eyes shouldn’t sting when you swim. Remember, it is a common myth that it is the chlorine, not the pH that causes your eyes to sting when swimming.

Pool water testing

How do I adjust pH?

The pH of water goes either up (more alkaline) or down (more acidic). The two most common ways used to adjust pH is using hydrochloric acid to lower it and buffer (sodium bicarbonate) to raise it. Soda ash can also be used to raise pH but this often results in the water turning cloudy.

Your local pool shop will be able to tell you how much of each material is required to adjust your pH correctly when they test the pool water. However, many pool owners who test the water themselves will often know how much is needed based on past experience.

Should I buy a pH controller for my pool?

Acid feeders for swimming pools are becoming more popular, particularly in upmarket pools. This is because these systems automatically adjust the pH using probes in the pipework. These probes measure the pH several times a minute while the pump is running. These systems will then add hydrochloric acid to the pool as required. This will then adjust the pH of pool water to the desired level.

What should I consider before buying a pH controller?

While these systems are very convenient, there are two things to consider before purchasing. First, the probes in these systems require regular maintenance. They need to be removed, cleaned and calibrated from time to time. This is most often done at the pool shop for a fee.

Secondly, as the probes age they need to be replaced. Remember, probes are often several hundred dollars to buy and need to be calibrated before installation. These probes also become less accurate as they age. Therefore, it can mean that the pool is out of balance, even though the system still says that the water is perfect. In short, pH controllers are low maintenance, not no maintenance.

Transporting pool acid

Hydrochloric acid
Drums of acid weigh 22kgs and can be very heavy for some people.

Another issue to consider is transporting and handling the drums of acid needed to run the units. If your system detects that the pH is high, it will draw the needed acid from a 25 litre drum of diluted hydrochloric acid. However, transporting heavy drums of acid is not easy for some people to handle without assistance.

What are the benefits of stable pH

If your systems are maintained properly, they will regulate the pH of the water almost perfectly. This stability means that your chances of pool surface issues or water chemistry problems are greatly reduced. Some of these pool surface issues can cause significant surface damage. They can also cost more than $10,000 to rectify in some cases. While there is no perfect solution, a pH controller should be considered if you are not able, or interested in maintaining your pool regularly.

You can find more detailed information about pH and what it means here.